[PATCH] KVM: x86: remove "full" out-argument from flush_tlb_gva
From: Paolo Bonzini
Date: Thu Sep 17 2026 - 06:13:14 EST
The "full" out-argument in flush_tlb_gva is only ever set on AMD
processors, where the TLB flush is little more than a memory write and
thus extremely cheap anyway.
Simplify the code by letting the implementation of Hyper-V TLB flush
hypercalls always go through all the addresses queued in tlb_flush_fifo;
there are no performance concerns since that is already the case on
VMX, and also was on SVM prior to commit 26505e1b5b54 ("KVM: SVM: make
svm_flush_tlb_gva do a full asid flush if NPT enabled", 2026-08-06).
Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/hyperv.c | 7 +++----
arch/x86/kvm/mmu/mmu.c | 2 +-
arch/x86/kvm/svm/svm.c | 4 +---
arch/x86/kvm/vmx/main.c | 4 ++--
arch/x86/kvm/vmx/vmx.c | 2 +-
arch/x86/kvm/vmx/x86_ops.h | 2 +-
7 files changed, 10 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 683bb8bf43a9..283847619ff8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1578,7 +1578,7 @@ struct kvm_x86_ops {
* Can potentially get non-canonical addresses through INVLPGs, which
* the implementation may choose to ignore if appropriate.
*/
- void (*flush_tlb_gva)(struct kvm_vcpu *vcpu, gva_t addr, bool *full);
+ void (*flush_tlb_gva)(struct kvm_vcpu *vcpu, gva_t addr);
/*
* Flush any TLB entries created by the guest. Like tlb_flush_gva(),
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 604651cb2739..3ee6bf35d1e4 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1995,7 +1995,6 @@ int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
u64 entries[KVM_HV_TLB_FLUSH_FIFO_SIZE];
int i, j, count;
gva_t gva;
- bool full = false;
if (!tdp_enabled)
return -EINVAL;
@@ -2006,7 +2005,7 @@ int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
count = kfifo_out(&tlb_flush_fifo->entries, entries, KVM_HV_TLB_FLUSH_FIFO_SIZE);
- for (i = 0; i < count && !full; i++) {
+ for (i = 0; i < count; i++) {
if (entries[i] == KVM_HV_TLB_FLUSHALL_ENTRY)
goto out_flush_all;
@@ -2015,11 +2014,11 @@ int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
* pages to flush.
*/
gva = entries[i] & PAGE_MASK;
- for (j = 0; j < (entries[i] & ~PAGE_MASK) + 1 && !full; j++) {
+ for (j = 0; j < (entries[i] & ~PAGE_MASK) + 1; j++) {
if (is_noncanonical_invlpg_address(gva + j * PAGE_SIZE, vcpu))
continue;
- kvm_x86_call(flush_tlb_gva)(vcpu, gva + j * PAGE_SIZE, &full);
+ kvm_x86_call(flush_tlb_gva)(vcpu, gva + j * PAGE_SIZE);
}
++vcpu->stat.tlb_flush;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 064ecc33b926..3d4c4937f679 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6704,7 +6704,7 @@ void kvm_mmu_invalidate_addr(struct kvm_vcpu *vcpu, struct kvm_pagewalk *w,
if (is_noncanonical_invlpg_address(addr, vcpu))
return;
- kvm_x86_call(flush_tlb_gva)(vcpu, addr, NULL);
+ kvm_x86_call(flush_tlb_gva)(vcpu, addr);
if (tdp_enabled)
return;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ea647938a2a6..835e59ca982c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4245,7 +4245,7 @@ static void svm_flush_tlb_guest(struct kvm_vcpu *vcpu)
svm_flush_tlb_asid(vcpu);
}
-static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva, bool *full)
+static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -4261,8 +4261,6 @@ static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva, bool *full)
}
svm_flush_tlb_guest(vcpu);
- if (full)
- *full = true;
}
static inline void sync_cr8_to_lapic(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 4c52ab8d0786..0ff3230fd95e 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -543,12 +543,12 @@ static void vt_flush_tlb_current(struct kvm_vcpu *vcpu)
vmx_flush_tlb_current(vcpu);
}
-static void vt_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr, bool *full)
+static void vt_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr)
{
if (is_td_vcpu(vcpu))
return;
- vmx_flush_tlb_gva(vcpu, addr, full);
+ vmx_flush_tlb_gva(vcpu, addr);
}
static void vt_flush_tlb_guest(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 504630f0eb40..e3bfe6aca1a0 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3377,7 +3377,7 @@ void vmx_flush_tlb_current(struct kvm_vcpu *vcpu)
vpid_sync_context(vmx_get_current_vpid(vcpu));
}
-void vmx_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr, bool *full)
+void vmx_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr)
{
/*
* vpid_sync_vcpu_addr() is a nop if vpid==0, see the comment in
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 054fd14bb2e1..cdb38d940cfb 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -82,7 +82,7 @@ void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags);
bool vmx_get_if_flag(struct kvm_vcpu *vcpu);
void vmx_flush_tlb_all(struct kvm_vcpu *vcpu);
void vmx_flush_tlb_current(struct kvm_vcpu *vcpu);
-void vmx_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr, bool *full);
+void vmx_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr);
void vmx_flush_tlb_guest(struct kvm_vcpu *vcpu);
void vmx_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask);
u32 vmx_get_interrupt_shadow(struct kvm_vcpu *vcpu);
--
2.52.0